General description

Even in the case where the 3 rows independent feed roller arrangement is adopted, there can occur a problem of curved transport of glass substrates if any proper provisions to equalize the frictional force at all contact points between substrates and rollers are not provided.

Explanation

In Vol. 295, it was explained that 3 rows independent feed roller arrangement would be more favorable for transfer of thin substrates.This session explains the direction of transfer of substrates in this structural design.

1) The number of rollers arranged

・ In order to eliminate possible effects of unstable force for transport due to any deflected substrates, consideration may be given to increased number of substrate support points, thereby ensuring stabilized loading and frictional force at each point of contact with a roller.
・ In practice, however, the above-described solution alone cannot necessarily equalize the frictional force at all points of contact with the backs of substrates.

2) Stabilized transfer of glass substrates

・ To guide the loads being transported to move straight on the transfer line, the direction of action of frictional force for transport must be made straight.
・ There is no correlation between increasing the number of roller support points for substrates and making the direction of action of frictional force for transport straight.
・ If the frictional force acting on the feed rollers becomes unbalanced, the loads being transported fail to move straight but their transport direction changes, resulting in transport problems.
・ Fig.1 illustrates possible behavior of substrates being transported when the frictional force acting on the feed rollers differs between roller positions, or in this Figure, the frictional force is largest at the leftmost position followed by the middle and rightmost positions.Possible reasons why the frictional force becomes different include 1. bent shaft connecting the feed rollers, 2. partially or unevenly worn feed rollers, and 3. inclined horizontal reference for the transfer machines.
・ Therefore, in addition to the adoption of the 3 rows independent feed roller arrangement, proper provisions must be made to equalize the frictional force on the feed rollers supporting the substrates.